Date of Award


Document Type

Honors Thesis (Colby Access Only)


Colby College. Biology Dept.


Andrea R. Tilden

Second Advisor

Tariq Ahmad

Third Advisor

Lynn Hannum


Melatonin is an indoleamine hormone whose primary role is the modulation of circadian rhythms by signaling photoperiod length. In vertebrates, it achieves this function, along with a number of other behavioral and physiological functions, through its three membrane-bound receptors, MT1, MT2, and MT3. While we know that melatonin is expressed endogenously in invertebrates, and numerous studies have demonstrated its similar functions to vertebrate melatonin, no specific protein has ever been identified as a true melatonin receptor in arthropods. My study used a wide variety of bioinformatics tools to provide genomic evidence of the existence of membrane-bound melatonin receptors in the crustacean, Daphnia pulex. Through my bioinformatics research, I identified several candidate proteins and examined their three-dimensional structure and function based on known protein models. Two of these proteins showed high structural and functional similarity to vertebrate MT2, and are strong candidate crustacean melatonin receptors.


melatonin, crustacean, melatonin receptor, Daphnia pulex, bioinformatics, arthropod melatonin